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Oxalic Application

I was wondering if any commercial beekeepers have tried an oxalic application when feeding pollen supplement. During the winter I feed my patties in the middle; so I already have the split and if applied in mid to late December the hive should be as shut down as much as possible.

Re: Oxalic Application

Because it is a substance which naturally occurs in honey, spinach, and several other foods - and it's safe effective, and cheap? Also the levels of OA in the hive return to normal levels quite quickly - or so I have heard. However even though it is approved - and widely used - in almost every other country it doesn't seem to be here in the USA. Odd.

However in places where it IS used, late fall after hives become mostly broodless seems to be typical - even where winters are cold.

Re: Oxalic Application

I don't really see a problem with that Matt, if the hives are broodless and the temps arent too cold I would say the sooner the better (assuming you feel that your mite numbers justify it. There have been some studies showing that oxalic can result in a decrease of brood shortly after application. Splitting a double is an excellent way to get the treatment to the cluster. Smaller hives dont seem to tolerate it very well though. We have had good results with a 3.2% solution.

"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

Re: Oxalic Application

Perhaps different states have different policies on the usage of a substance in a beehive. Because something be not officially approved, does that make it an offense to use or merely an offense to promote or claim it as an approved miticide.

Re: Oxalic Application

I talked briefly with a state inspector - I'll not say which state - and he was evasive in a manner which led me to believe that it may or may not be a gray area which he would be inclined to overlook/not ask about. IE "I'll get back to you..." or rather never mention this again.

Re: Oxalic Application

oblib, we are going to bleach the wooden wares in a couple of hives. Will wait a week or two and check there is no brood. Have the finishing touches to put on a DIY glow plug oxalic acid vaporiser, though I understand it is approved in Canada as I purchased OA chrystals from a bee keeping supplier.

Re: Oxalic Application

Originally Posted by jim lyon

I don't really see a problem with that Matt, if the hives are broodless and the temps arent too cold I would say the sooner the better (assuming you feel that your mite numbers justify it. There have been some studies showing that oxalic can result in a decrease of brood shortly after application. Splitting a double is an excellent way to get the treatment to the cluster. Smaller hives dont seem to tolerate it very well though. We have had good results with a 3.2% solution.

The above quote regarding a decrease of brood is what I am trying to get a complete understanding of. I am wondering if a patty would counteract any decrease in brood rearing. Most of my almond contracts have a frame commitment; I wouldn't want to knock back a 10 frame colony to a six right before almonds. Buy the idea of hitting the mites when they are exposed with an effective soft treatment is appealing.

Re: Oxalic Application

That is why I am suggesting the sooner the better but I really doubt that its a concern. I'm not aware that there has ever been any evidence that an oxalic application can cause a future reduction in brood only that one study somewhere claimed a reduction in brood shortly after application compared to a control. FWIW I have used oxalic when a lot of brood was present and never noticed any slowdown in those hives from casual observations.

"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

Re: Oxalic Application

Is there not a considerable difference in Oxalic syrup dribble or liquid spray and the application by heat vaporization of the dry chrystals. In the latter, you do not have to open the hive and does not wet the bees. Have read somewhere that the dribble method should only be done once but fuming can be done any number of times.

Re: Oxalic Application

Irwin, that is a pretty fancy machine. We have used the drip method for a few years but this year we purchased the varrox vaporizer to try. The things I like about this method is it can be done after the hives are wrapped without opening them and with our conditions here that is important. It does an very good job of filling the two brood chmabers with vapour. If you follow the direction for timing with this unit it works like a charm. (burn time and wait time) It also has to be about the lowest cost treatment going and mites should not develop a resistance to it. The only thing negative is it is slow to use. It took us about 6 minutes a hive so you need more than one unit if you are doing a lot of hives.

Re: Oxalic Application

I would hardly call my vaporizer fancy, something I thought a bit about and tinkered with till I was half happy, it cost me a lot less than $100 ( used parts ).I supplement the heat source from the glow plug with a little propane heat , by using a little more oxalic in the burn chamber I can do two hives in the time it would take to do one.You are right there are a lot of pluses in the use of oxalic sublimation to treat mites this time of year under our conditions, hives being wrapped , COST of treatment, etc.And the only big fault is the time it takes per colony.
I have been following Allan Dick's fall treatment at http://www.honeybeeworld.com/diary/default.htm. He used a Cowan vaporizer with four units,so four hives could be done at one time,I hope to build something similar.Cowan currently wants $6600 for their machine.This maybe relatively cheap when you consider the cost of strips and having to use them for a number of years
I hope to shoot a video of my vaporizer in operation and show how it works

Re: Oxalic Application

I load 5-6 grams of oxalic into the the first pipe fitting coming off the bottom of the galvanized tee. It is a brass 3/.4" reducer fitting where the head of the glow plug resides , that supplies the heat.The next 3 pipe reducers allow me to thread the glow plug into the last reducer. The 12 volt blower certainly helps to move the oxalic vapor through the hive, I block the bottom entrance with a piece of wet towel , the vapor can bee seen exiting the top entrance,which I leave open.
honeybeeworld has a video of Cowans vaporizer killing mites at https://skydrive.live.com/?cid=7a1f9...1354&sc=photos